1. Field of the Invention
The present invention relates to a storage controller.
2. Description of the Related Art
A storage controller is an apparatus that provides a host computer (hereinafter “host”) with a relatively large capacity storage area. The storage controller, for example, uses a plurality of hard disk drives to construct a storage area based on RAID (Redundant Array of Independent Disks). A logical volume, which is a logical storage area, is configured on the physical storage areas of the respective hard disk drives. The host can carry out the reading and writing of data from and to the logical volume.
Now then, a storage controller that daisy chains together a main case, which is in charge of control functions, and an expansion case, which is in charge of storage functions, is known (JP-A-2007-011682). A controller and a plurality of hard disk drives is mounted in the main case, and a plurality of hard disk drives is mounted in the expansion case.
In the prior art storage controller, the user can expand the storage capacity of the storage controller by adding an expansion case as needed. However, adding more expansion cases enlarges the size of the storage controller.